In recent years, open systems and virtualization of servers has become popular, and the management of system has become more complex. Hence, from the perspective of achieving easiness in managing systems and having flexibility toward the rapidly increasing data volume, it is becoming common practice to implement storage systems.
In a storage system, the performance of the storage system is adjusted by adjusting the bandwidth limitation of the data transfer paths provided among volumes and a server that executes applications. As a specific example of bandwidth limitation, the bandwidth is automatically assigned according to the priority of the tasks. In that case, for example, an upper limit of the bandwidth is decided for the tasks having low priority, and the bandwidth used by the tasks having low priority is adjusted within the range of the upper limit, and the freed bandwidth is used in the tasks having high priority.
Conventionally, regarding the adjustment of the bandwidth limitation, a target value is specified using a response time that serves as an easy-to-specify value for the user, and the storage system adjusts the bandwidth in such a way that the response time of the targeted task satisfies the specified target value.
As a performance adjustment technology in such an information processing system, in order to achieve the target performance, a conventional technology is known for calculating the processing time excluding the standby time required for locking the database records. Moreover, a conventional technology is known for varying the performance target value on an application-by-application basis. Furthermore, a conventional technology is known for performing priority control of the accesses according to the level of the service provided by a virtual machine. Moreover, a conventional technology is known for deciding the priority of an access request based on the attribute of the client issuing the access request.
Patent Document 1: Japanese Laid-open Patent Publication No. 2013-57996
Patent Document 2: Japanese Laid-open Patent Publication No. 2015-191324
Patent Document 3: Japanese Laid-open Patent Publication No. 2013-206229
Patent Document 4: Japanese Laid-open Patent Publication No. 2006-67401
However, in the conventional bandwidth adjustment, the actually-measured response time and the target response time is compared, and the bandwidth is accordingly varied in a stepwise manner so as to approach the bandwidth at which the target response time is achieved. Since the bandwidth is adjusted in a stepwise manner, it takes time to reach the appropriate bandwidth, thereby making it difficult to follow unexpected or rapid changes in the input-output (IO).
Moreover, in the conventional technology of calculating the processing time excluding the standby time required for locking or in the conventional technology of varying the performance target value on an application-by-application basis, since the change in performance occurs in a stepwise manner, adjusting the bandwidth takes time. The same is the case in the conventional technology of performing priority control of the accesses according to the service level or in the conventional technology of deciding the priority based on the attribute of the client. Thus, it is a difficult task to adjust the bandwidth in an expeditious manner.